As is common practice, winches, hoists, and other power devices requiring resistance to driven torque often employ brake mechanisms to satisfy various design criteria. Winches, hoists, and the like typically employ a motor that drives a gear train, which is coupled to a drum. The motor is often capable of being driven in opposite rotary directions, which is commonly referred to as “power-in” and “power-out” directions. When the motor is not actuated (i.e. idle), it is typically preferable that the drum is stationary thereby opposing any external loads or driven torque.
The brake mechanisms of these devices often utilize a series of brake or friction plates that provide an opposing force when engaged that minimizes or prevents movement of the drum in response to any external driven torque. In essence, these brake mechanisms lock the power device to permit “holding” while under load.
However, traditional brake mechanisms suffer from a number of disadvantages. For example, traditional brake mechanisms are incapable of eliminating drag associated with the brake mechanism when the device is being driven in the power-in direction. Similarly, traditional brake mechanisms often suffer from excessive drag that inhibits efficient operation when the device is being driven in the power-out direction. Still further, traditional brake mechanisms are often incapable of distinguishing between drive torque and driven torque and, thus, may lead to excessive drag on the device or insufficient holding capacity.
Accordingly, there exists a need in the relevant art to provide a brake mechanism for use with a winch, hoist, or similar power device that is capable of eliminating drag associated with a power-in drive motion. Similarly, there exists a need in the relevant art to provide a brake mechanism for use with a winch, hoist, or similar power device that is capable of minimizing drag associated with a power-out drive motion. Still further, there exists a need in the relevant art to provide a brake mechanism for use with a winch, hoist, or similar power device that is capable of overcoming the limitations of the prior art.